Why is my Asus t100ta in tablet mode trying to use Excel - says control key is stuck & can't input data?

[Windows Central Question]

asus t100ta in tablet mode trying to use excel - says control key is stuck & can't input data

I am trying to use excel in tablet mode - when i start excel it says control key is on do I want to start in safe mode - if I start excel it won;t let me input anything - it just keeps trying to forma cell ...... help